1. Field of the Invention
The present invention relates to a plasma display panel (PDP) and a method for manufacturing the PDP.
The PDP has drawn attention as a thin display device with a wide viewing angle. As being in wide use as a HDTV (high-definition television), a high-performance PDP with higher luminance is desired.
2. Description of the Prior Art
A surface discharge type AC plasma display panel is in use as a large screen display device for a television set. The surface discharge type mentioned herein has a three-electrode structure having first display electrodes and second display electrodes to be anodes and cathodes in display discharge for determining light emission quantity of a cell and address electrodes. The first and second display electrodes are arranged in parallel to each other on a front or rear substrate, while the address electrodes are arranged so as to cross the display electrode pairs. There are two types of arrangement of the display electrodes: one is a type in which a pair of display electrodes is arranged for each row in a matrix display; another is a type in which each of the first display electrodes and each of the second display electrodes are arranged alternately at regular intervals. In the latter case, every three display electrodes correspond to two rows and each display electrode except both ends of the arrangement works for a display of neighboring two rows. The surface discharge type allows a fluorescent material layer for a color display to be arranged away from the display electrode pair in the direction of the panel thickness; thus deterioration of the fluorescent material layer due to ion bombardment in the discharge can be reduced. The surface discharge type is suitable for realizing long life of color screen in comparison with an opposed discharge type in which first display electrodes and second display electrodes are separately arranged on a front substrate and a rear substrate.
In the conventional PDP, display electrodes are formed by patterning a conductive thin film formed on a substrate. More specifically, each of the display electrodes is an elongated film conductor and the surface (the discharge surface) thereof is substantially parallel to the substrate surface.
Conventionally, discharge starting voltage of the surface discharge type is higher than that of the opposed discharge type having approximately the same gap length as the surface discharge type; therefore there is a problem that the light emission efficiency is low.
It is an object of the present invention to provide a PDP having a novel cell structure that excels in light emission efficiency. It is another object of the present invention to provide a method for manufacturing a PDP having a novel cell structure with high productivity.
According to one aspect of the present invention, there is provided a plasma display panel in which each display electrode arranged on a first substrate making a substrate pair is formed in a manner to have a three-dimensional structure including an elongated power supplying portion stretching over plural cells aligned in one direction, and discharge portions protruding from the power supplying portion in the direction of electrode arrangement for each cell so as to be close to a second substrate. Thereby, main surfaces contributing to discharge between the display electrodes are so arranged that each of the main surfaces is approximately orthogonal to the substrate surface and is opposed to the main surface of the neighboring display electrode across a discharge gas space. Under a structure in which the distance between the discharge portions in neighboring display electrodes is shorter than the distance between the power supplying portions, when drive voltage is applied between the neighboring display electrodes, an area where discharge is easy to occur the most in each cell is between the discharge portions opposed to each other. The three-dimensional structure of each of the display electrodes can be attained by a method of forming grooves on the substrate, providing a conductive film to cover the bottom and the side surfaces of the grooves and patterning the conductive film.
The discharge type is classified into opposed discharge between the electrodes across the gas space (however, the direction of charge transfer is not the direction of the panel thickness but the direction along the substrate surface). This discharge type is referred to as xe2x80x9csurface direction opposed dischargexe2x80x9d. Since the main surfaces are opposed to each other in the surface direction opposed discharge, discharge starting voltage is low in comparison with the conventional surface discharge. Additionally, selection of areas of the discharge portions allows discharge current to be optimized; thus light emission efficiency can be enhanced.